title: Laser surface modification of 316 L stainless steel with bioactive hydroxyapatite.
abstract: Laser-engineered net shaping (LENS™), a commercial additive manufacturing process, was used to modify the surfaces of 316 L stainless steel with bioactive hydroxyapatite (HAP). The modified surfaces were characterized in terms of their microstructure, hardness and apatite forming ability. The results showed that with increase in laser energy input from 32 J/mm(2) to 59 J/mm(2) the thickness of the modified surface increased from 222±12 μm to 355±6 μm, while the average surface hardness decreased marginally from 403±18 HV0.3 to 372±8 HV0.3. Microstructural studies showed that the modified surface consisted of austenite dendrites with HAP and some reaction products primarily occurring in the inter-dendritic regions. Finally, the surface-modified 316 L samples immersed in simulated body fluids showed significantly higher apatite precipitation compared to unmodified 316 L samples.
authors.affiliation: CSIR-Central Glass & Ceramic Research Institute (CGCRI), 196, Raja S. C. Mullick Road, Kolkata 700032, India. Electronic address: vamsiballa@cgcri.res.in.
authors.forename: Vamsi Krishna
authors.initials: VK
authors.lastname: Balla
authors.forename: Mitun
authors.initials: M
authors.lastname: Das
authors.forename: Sreyashree
authors.initials: S
authors.lastname: Bose
authors.forename: G D Janaki
authors.initials: GD
authors.lastname: Ram
authors.forename: Indranil
authors.initials: I
authors.lastname: Manna
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D006244:Hardness; D007834:Lasers; D013193:Stainless Steel / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D013193:Stainless Steel; D017886:Durapatite
keywords: Biocompatibility; Hydroxyapatite; Implant; LENS™; Laser surface modification; Stainless steel